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Hot Bob
01-11-2010, 09:44 AM
Like the title says; I'm shopping for a co-ax. Can you guys make some recommendations on a decent quality unit. I've been using an edge finder and I think I'd feel more comfortable with a co-ax for locating holes. Like to hear your comments. Price is always a factor.

Bob

Boucher
01-11-2010, 10:01 AM
Several years ago I bought a cheap one. It works but the small screws are pretty bad and cause it to be a little harder to use. In hindsight I wish that I had bought a Blake. There have been several threads lately that recommend a different type indicator. I have not used mine as much as I thought I would. I probably would use a better one more but that is pretty expensive if it is just going to set in the tool box.

Black_Moons
01-11-2010, 10:05 AM
hot bob: Before buying a new toy, How about a new use for an old one?

If you have a test dial indicator and a shaft (or lathe to make one) to mount it to, you can chuck that shaft or use a collet/etc, (I made a shaft in the lathe that is 3/8" for 3/4" then 1/2" for the rest of the length untill it shrinks to the diamiter required to mount one of those clamps from my mag bases, so it fits in both 3/8" and 1/2" collets and converts to something a TDI can easily be mounted to)

I actualy had an accident while making this shaft that bent it horrabley. I managed to unbend most of it on the bench, but thankfuly for this application it does not need to be straight.

Anyway, Mount the dial indicator onto your shaft, and just manualy turn the spindle with your drawbar wrench or whatever at the top and watch the dial indicator and adjust the table. Slightly harder to read when its facing your collumn then a coax, but much much cheaper! And guarenteed to be about as accurate as your TDI :)

Also note, messure both sides of a hole, devide the diffrence, and thats exactly where the needle has to be on the TDI to be 'centered' along that axis, Reguardless what angles the TDI arm is at.

Just like a flycutter, it does not matter how straight the shaft is or what angle its affixed to the shaft, as the spindle will make it rotate in a perfict circle.

this method is likey more accurate for large holes as well, as a co-ax indicator needs a long 'feeler' arm for large holes, and hence that reduces the movement on the co-ax indicator dial per mil of runout, where as a TDI you just mount further out from the spindle axis for bigger holes.

Same setup can be used to tram your mill as well btw.

RTPBurnsville
01-11-2010, 10:16 AM
I have a cheap one from CDCO but have been happy with it's operation. If I remember correctly it cost < $75 and came in a decent wood box with foam padding.

MickeyD
01-11-2010, 10:32 AM
If you want a co-ax save your money and buy a Blake, there really is a difference in the quality over the imports. Penn Tool has them for about $250 new but a nice used ones normally go for not much more than the imports do.

lazlo
01-11-2010, 10:42 AM
What Mike said. Lately, there have been a bunch of brand-new Blakes for sale on Ebay, for about half of retail price ($125 - $150).

dp
01-11-2010, 10:57 AM
I have one of the "fake Blake" units and while I can see issues of refinement it works very well for me. It is a relative reading vs absolute reading instrument so short of binding in the moving parts, which mine definitely does not have, it is proving to be a frequently used tool for specific purposes: centering the quill over a hole or pin, tramming my mill, aligning a vise or other fixture. I like that the dial is always visible vs a DTI which requires some gyrations to use iin all positions. The co-ax is less sensitive than a DTI and it doesn't get used where that is an issue.

JTToner
01-11-2010, 11:29 AM
Either a Blake or a Blake. I have both a Blake and a chi-com imitation. The best thing about the chi-com unit is that if it were bigger, heavier, and I had a boat.........

Johnny

dp
01-11-2010, 11:44 AM
Either a Blake or a Blake. I have both a Blake and a chi-com imitation. The best thing about the chi-com unit is that if it were bigger, heavier, and I had a boat.........

Johnny

And that is probably the best evaluation possible. Some of us have one or the other but not both. Specifically what do you experience that differentiates them? I'm curious to see if these are issues I'm aware of in my not Blake version.

cuslog
01-11-2010, 11:51 AM
I had looked at the Blakes but up here they were about $350 - too much for my little home shop. Then I saw them for $48 at CDCO and I thought "I'll bite". For that price I have no regrets but then I'm not working to tenths either.

SpyGuy
01-11-2010, 12:01 PM
I'd love to try a Haimer Centro (http://www.haimer-usa.com/usa/taster-centro.php). But I'm sure the cost would knock me flat.

JTToner
01-11-2010, 08:12 PM
What my Fake Blake does is that the indicator needle jumps with every revolution.Its a sudden jump as if the little rotating arm was hitting a burr or a pit on the mating surface, but there is nothing that I can see. Also, and noted above, the screws must be made from recycled Yugos.

Johnny

pressurerelief
01-11-2010, 08:24 PM
For a discussion on Haimer take a look at,

http://bbs.homeshopmachinist.net/showthread.php?t=38338&highlight=haimer

The Blake has one advantage in that it can be serviced in the US by Long Island Indicator. My Haimer has to go back to Germany for Service. Do not ask how I know this little tid bit.

P/R

oldtiffie
01-11-2010, 08:44 PM
I'd love to try a Haimer Centro (http://www.haimer-usa.com/usa/taster-centro.php). But I'm sure the cost would knock me flat.

The title of the thread (OP) is "Shopping for a quality co-ax".

It really depends on how and what you define "quality" to be and how much of it you need (or want?) and how much you are prepared to pay for the use you intend to give it and the results you want from it.

Another consideration is the amount of "head room" the co-ax will need or use and whether you have to move your head (round or square column) or "knee" (BP type mill) up or down after removing the co-ax and how comfortable you are that the "line" of the co-ax and the job will still be within your limits after any such necessary move.

I have a Chinese-made "fake Blake" co-ax and I am quite satisfied with it. I doubt that any possible better performance by a Blake or other "better" co-ax would justify the additional cost.

I am in OZ (Australia) and bought mine from either LittleMachineShop or CDCOtools in the US (forget which - but the service at both is excellent).

I bought mine ti see if the current crop of co-ax's was better than some (so-called) "really good" ones quite some years ago that the shop I was in had real "issues" with. I have to say that the Chinese "Fake Blake" was excellent value and does all I ask of it.

I still prefer to use a good test dial indicator though.

http://i200.photobucket.com/albums/aa294/oldtiffie/measuring/Co-axialindicator1.jpg

http://i200.photobucket.com/albums/aa294/oldtiffie/measuring/Co-axialindicator2.jpg

http://s200.photobucket.com/albums/aa294/oldtiffie/measuring/?action=view&current=Co-axialindicator2.jpg

http://i200.photobucket.com/albums/aa294/oldtiffie/measuring/Dialindicator3.jpg

http://i200.photobucket.com/albums/aa294/oldtiffie/measuring/Dialindicator8.jpg

Mike Nash
01-11-2010, 09:17 PM
What my Fake Blake does is that the indicator needle jumps with every revolution.Its a sudden jump as if the little rotating arm was hitting a burr or a pit on the mating surface, but there is nothing that I can see. Also, and noted above, the screws must be made from recycled Yugos.

Johnny

I've got a jumpy one also. I got mine from CDCO a few years ago. Luck of the draw we got "bad" ones I guess.

SGW
01-11-2010, 09:39 PM
If you're feeling ambitious, Guy Lautard has plans for one in a volume of his "machinist's Bedside Reader" series.

recoilless
01-11-2010, 10:28 PM
[http://bbs.homeshopmachinist.net/showthread.php?t=37241&highlight=co+axial+indicator

Above link has some timely info.

MaxxLagg
01-11-2010, 10:28 PM
If you're feeling ambitious, Guy Lautard has plans for one in a volume of his "machinist's Bedside Reader" series.

I have volumes 2 and 3. Anybody want to email me scans of the plans from volume 1?
kenneth.f.ford@gmail.com

J. R. Williams
01-11-2010, 10:45 PM
My vote is for the Blake. I have my unit mounted in a dedicated tool holder for my milling machine. It has served me well for over 15 years. The cheap import probes will work in the Blake as I had to replace on probe that I hit and it broke.

JRW

SpyGuy
01-11-2010, 11:12 PM
I'd love to try a Haimer Centro. But I'm sure the cost would knock me flat.
The title of the thread (OP) is "Shopping for a quality co-ax".
Thanks mom for reminding me.

But since it seems you didn't bother to check the link I provided, I should inform you that the Haimer Centro IS a quality co-axial indicator. Just because it's not a Blake or a Blake knock-off, that does not make it irrelevant to this thread.

DaHui
01-12-2010, 12:40 AM
I just bought a nice Blake on ebay. There are usually a few decent looking ones at any given time. How much accuracy do you require?

dp
01-12-2010, 12:45 AM
I just bought a nice Blake on ebay. There are usually a few decent looking ones at any given time. How much accuracy do you require?

I don't know that accuracy is something you get with a Blake or other co-ax. You get more or less sensitivity, and repeatability. Accuracy means you need to know what the deflection means and with the exception of one configuration that's not something the Blake and clones provide. The tick marks and numbers on the dial don't have much value. In another thread recently I suggested there could be Disney characters on the dial for all the good they do.

Edit: Rather than rehash all the various bedevilments and wonders of co-axial indicators, here's link to a fascinating thread on the subject that turned these devices inside and out: http://bbs.homeshopmachinist.net/showthread.php?t=37241

And of course there's my video of one in action: http://www.youtube.com/watch?v=ZfioLDhBNBQ

oldtiffie
01-12-2010, 01:09 AM
Originally Posted by oldtiffie

Originally Posted by SpyGuy
I'd love to try a Haimer Centro. But I'm sure the cost would knock me flat.
The title of the thread (OP) is "Shopping for a quality co-ax".


Thanks mom for reminding me.

But since it seems you didn't bother to check the link I provided, I should inform you that the Haimer Centro IS a quality co-axial indicator. Just because it's not a Blake or a Blake knock-off, that does not make it irrelevant to this thread.
Thanks for the thanks.

The OP said:

Like the title says; I'm shopping for a co-ax. Can you guys make some recommendations on a decent quality unit. I've been using an edge finder and I think I'd feel more comfortable with a co-ax for locating holes. Like to hear your comments. Price is always a factor.

Bob

I didn't and still can't see where the OP specifically mentioned or included any particular "name" or source, and neither did he exclude any either.

I don't see where I excluded - or criticised or maligned any - Hamer Centro included - either.

On further reflection, I guess I may have unintentionally seemed to have maligned or impugned you and/or the Haimer Centro co-ax and if you feel that way then I apologise.

oldtiffie
01-12-2010, 04:44 AM
Originally Posted by DaHui
I just bought a nice Blake on ebay. There are usually a few decent looking ones at any given time. How much accuracy do you require?


I don't know that accuracy is something you get with a Blake or other co-ax. You get more or less sensitivity, and repeatability. Accuracy means you need to know what the deflection means and with the exception of one configuration that's not something the Blake and clones provide. The tick marks and numbers on the dial don't have much value. In another thread recently I suggested there could be Disney characters on the dial for all the good they do.

Good question and a good answer.

Here is the accuracy table from the Blake web-site:
http://i200.photobucket.com/albums/aa294/oldtiffie/measuring/Co-axindicator-Blake-adjustmentfact.jpg

If you have a look at the 2" feeler you will see that other than the 4" diameter, each scale division is pretty accurately aligned to 0.0005" TIR (ie "5 tenths" Total Indicated Run-out).

The single scale for a the 4" feeler is about double the 2" (~0.0005" x 2 ~ 0.0010").

The single scale deflection for the 6" feeler is about 3 x the 2" (~0.0005" x 3 ~ 0.00146").

So - for instance in a 2" bore using a 2" feeler an actual 0.0005" TIR will be indicarted as 0.0005" - which is pretty good.

In a 2" bore using a 4" feeler an indicated 0.0005" TIR will be an actual 0.0010" - which is not so good as it is half as accurate.

In a 2" bore using a 6" feeler an indicated 0.0005" TIR will be an actual 0.0014" - which is not good as it is only one third as accurate.

Use the 2" feeler and the calibrations and the accuracy are very good.

dp (Dennis) made and showed a video of when he used the Co-ax for dynamic tramming as well as dynamic centreing in a bore. Both were really good. I pretty well bought my co-ax on the strength of that video alone.

Dennis' co-ax is a (Chinese) close and so is mine. I have no complaints about it at all as it works very well.

The BIG PLUS for the co-ax over the test indicator is that the co-ax can cope with a 30mm rise and fall over 240mm (~9 1/2") arc with the 100mm (4") feeler on it whereas my dial test indicator can only handle just over 1mm (~0.040") over any arc/swing. This rise and fall at the co-ax feeler end was accommodated by the 5mm (~0.200") travel in the body of the co-ax.

This is a big plus for "roughing in" the "tram" and depending upon your accuracy requirements - "fine tuning" your mill tram as well.

I could see that this might be the case in Dennis' video and it was the "clincher" that decided me to buy it.

First of all - the "Blake" table - again:
http://i200.photobucket.com/albums/aa294/oldtiffie/measuring/Co-axindicator-Blake-adjustmentfact.jpg

Here are the pics in my Sieg X3 mill:

First, with the Co-ax fully "up" (100mm ~4" feeler just touching the Sieg X3 table - (note the 5mm gap between the top of the body and the central piston flange) - sorry about the poor pic - I got it wrong:
http://i200.photobucket.com/albums/aa294/oldtiffie/measuring/Co-axialindicator8.jpg

Now the milling head has been lowered 30mm until the flange at the top of the piston has closed the gap with the top of the body of the co-ax:

http://i200.photobucket.com/albums/aa294/oldtiffie/measuring/Co-axialindicator9.jpg

I pretty well expected that from the Blake table.

So, if I use a smooth parallel tramming plate I can leave the co-ax in contact with the plate as I move the milling head for tram - a LOT more than I can with the 0.01mm Dial Test Indicator with its maximum 1.00mm travel.

ammcoman2
01-12-2010, 09:24 AM
I have a unit sold by SPI which I got "new" from Fleabay. Can't complain re the quality.

Geoff

JCHannum
01-12-2010, 09:32 AM
The Blake and their clones are made for locating center of a feature such as a bore, outside diameter or center punch mark. They are not made for any other purpose such as tramming in a table.

They will kinda-sorta work, but that is not their intended purpose. Long drawn out descriptions of the missapplication of a tool or instrument serve no purpose but to confuse the beginner and obfuscate the issue.

The table from the Blake site is not an accuracy table, is is a table of correction factors for the different length stylii. The dial graduation values are not an indication of error, but are multipliers to indicate the relative value of the graduations with the various length stylii. When the indicator is centered to zero movement, it is zero movement. If there is a +- deviation from the zero point, it is +- the graduation times the multiplier. That is not error.

S_J_H
01-12-2010, 09:41 AM
Jim, But what is wrong with using it for tramming? All you need is a comparative measurement. It matters none that the divisions are sort of meaningless.

Now, I can see where sensitivity will be much reduced using the co-ax for tramming..

Steve

JCHannum
01-12-2010, 09:54 AM
Steve,
There is nothing basically wrong with using it for tramming, but there is nothing basically wrong with using a screwdriver for a pry bar either. If you use a tool for other than it's intended application, you can expect nothing but poor results.

Black_Moons
01-12-2010, 10:13 AM
Heh at the number of screwdrivers iv chiped/abused before I decided to buy real pry bars.. Course.. I still sometimes grab a screwdriver for some god unknown reason.

I allways wondered how that thing transfered movement.. so the whole 'body' of the coax goes up and down? And I guess the feeler just acutates a cam?

Randyinaloha
01-12-2010, 10:24 AM
Gosh, have followed this thread for 3 pages before I figured out what you are talking about.
Co-ax is a term for electronic wiring and I wondered.
Now I know what you are talking about. Forgot that term in machining a long time ago.

I have been tool&die maker for 30 yrs. Mostly in injection molds.
Have a few dial indicators Interapid, Mitutoyo in .001 flavor.
1 .0001 dial indicator.
All have worked well. Of course $100 in 1970 was a lot of money.

There is a way to multiply the lenght of the feeler.
If I recall, the lenght from the center of the ball end to the center of the shaft that drives the indicator needle was .75000.
So use a lever with the long end to the work and divide by the short end.

All this aside I cannot see a milling machine doing better than .0005.

Have drilled .001 holes in a lab envoironment. Such fun.

Waiting to see an electronic digital come out. That would be neat.
Laser tech type. No contact.

dp
01-12-2010, 10:39 AM
Jim, But what is wrong with using it for tramming? All you need is a comparative measurement. It matters none that the divisions are sort of meaningless.

Now, I can see where sensitivity will be much reduced using the co-ax for tramming..

Steve

In my experiment the sensitivity is not reduced - in fact it is increased. I'm measuring the quill alignment on a long arm continuously, 360 around the table - a nearly 10" diameter. That is the same advantage as using a DTI on a 5" arm. Absolute Z-axis error magnitude is related to the length of the X and Y distances.

The functional advantage goes to the co-ax for allowing powered sweeping while keeping the dial facing the operator. Since we're looking for zero deflection and not absolute readings, the accuracy is as good as the dimensions of the brake rotor I sweep which I've tested and is quite adequate. In fact accuracy at zero deflection is a meaningless concept. If there is slop in the dial mechanism then that is another issue but I've seen no hint there is. As for sensitivity - calculate the tangent of an angle where the side adjacent is 10" long and side opposite (vertical deflection) is 0.0". It is infinite (I should say, infinitely small).

As for the applicability of the co-ax to tramming, I've shot that down solidly because I've done it as shown in the video I made. A tool is what you make of it.

What isn't shown in the video is that I swept the brake rotor and zero'd the deflection to my satisfaction by adjusting and shimming the post (I have a tilting post mill). Then I spun the rotor 180 and swept it again - no change in deflection direction or magnitude; still zero. Then I spun it 90 and repeated the sweep. Again, no change in deflection. Same for all angles of rotation of the rotor. Then I removed the rotor and measured the table directly. Still trammed. But on the Y axis I have only the depth of the table to measure so if it were off I'd be less able to measure that. This test tells me the rotor does not contribute any significant z-axis error. This is not terribly surprising given that parallelism and absence of potato chipping in brake rotors is quite good to prevent braking vibrations. How could I not be happy with the results?

JCHannum
01-12-2010, 10:41 AM
I allways wondered how that thing transfered movement.. so the whole 'body' of the coax goes up and down? And I guess the feeler just acutates a cam?

The body rises and falls. The stylus is attached to a lever that is pivoted on the center shaft. The lever lifts the body and the amount of lift is measured by a dial indicator. It is designed to be used under power not static.

This is my shop built co-ax, made from the Lautard/HSM plans. It shows the principle.

http://i320.photobucket.com/albums/nn351/jchannum/P1070407.jpg

Hot Bob
01-12-2010, 10:49 AM
Wow, lots of replies on this. Obviously there are some strong opinions. I appreciate all the feedback.

My needs: I have a small custom bike and hot rod shop. It is a one man show but it is how I make my living. I expect my tools to do the job for which I purchased them every time I use them. I don't like to buy throw-away tools as I think spending more for quality is usually a good investment. That said, like most, I can't always afford the best. Sometimes I have to compromise.

My mill is a 3ph Rong Fu RF-45 from Penn Tool. It is fitted with a Kurt vise, an Easson DRO, a Jacobs drill chuck, and import R8 collets from Enco. I use an Interapid test indicator. I try to work to half a tenth tolerance on anything that requires precision. I am not a machinist but, I have been doing machine work for over twenty years.

Based on the replies in this thread I'd say a Blake is probably the way I'll go. I'll most likely shop for a used one for a couple weeks but, if nothing comes up, I'll probably order from Long Island Indicator.

Lastly, I have to say that I couldn't disagree more with JCHannum. I can probably come up with five different ways of arriving at the desired result when working in the shop. Improvisation and adaptability are absolutely essential traits for turning out product. Poor results are the product of poor planning and poor execution, not the result of a limited tool arsenal.

Bob

JTToner
01-12-2010, 10:51 AM
One more thing about Blake - a few months ago I had a major brain fart and crashed the Blake, rendering it useless. I took it to their facility where, for a very reasonable charge, they rebuilt it to factory specification. Also, and this counts a lot with me, they are very nice people.

Johnny

JCHannum
01-12-2010, 11:10 AM
There is nothing wrong with improvisation and adaptation, they are a necessary part of shop work. But there is quite a bit wrong with missapplication.

When a measuring instrument such as the co-ax is misapplied, the results might or might not be what is desired. A knowledge of the basic function and limits of the instrument are necessary to be able to interpret the outcome. If it is the only tool at hand, use it, but make sure that you have a firm understanding what you are doing first.

The Blake co-ax is made for a specific application under specific operating conditions. It is a very handy tool and excellent for its intended purpose. If your need is for other purposes, better tools are available. For all around tramming and indicating the first purchase should be a good DTI with all attachments.

BobWarfield
01-12-2010, 11:20 AM
My cheap coax isn't "jumpy". I guess it is the luck of the draw with import tools, but barring a bad one, I couldn't see a reason to pay more for the name brand.

RE all the kvetching about Coax's threatening to break out in this thread and that did break out in the others, I was amused to discover that other thread had become famous in some local machine shops. They thought it was pretty funny peeps had such a hard time understanding both the value and the limitations of the tool. It was definitely a "roll their eyes" there-go-those-home-shop-guys-again kind of remark. LOL.

Cheers,

BW

dp
01-12-2010, 11:24 AM
There is nothing wrong with improvisation and adaptation, they are a necessary part of shop work. But there is quite a bit wrong with missapplication.

You're going to have to describe why it is a misapplication to tram with a co-ax because it's surely not obvious. That might be a good thread starter since we've brutally hijacked this one :)

dp
01-12-2010, 11:26 AM
RE all the kvetching about Coax's threatening to break out in this thread and that did break out in the others, I was amused to discover that other thread had become famous in some local machine shops. They thought it was pretty funny peeps had such a hard time understanding both the value and the limitations of the tool. It was definitely a "roll their eyes" there-go-those-home-shop-guys-again kind of remark. LOL.


Beyond rolling their eyes did they offer any useful information to help define the limitations? Eye rolling, while fun to watch, has always been one of those useless reactions that causes me to roll my eyes in wonderment.

JCHannum
01-12-2010, 12:01 PM
You're going to have to describe why it is a misapplication to tram with a co-ax because it's surely not obvious. That might be a good thread starter since we've brutally hijacked this one :)

Perhaps missapplication is not the best choice of words, 'not the intended application' might be better. It will work, but if a lot of people run out to buy a co-ax with just that purpose in mind, they might be somewhat disappointed.

It will work as described, but there are other methods that will work just as well. If you have a co-ax and choose to use it for this purpose, it will work.

gwilson
01-12-2010, 12:38 PM
DP: You really are making your co-ax less sensitive by using a long arm to tram with. I made that mistake too,until I realized that the co-ax was on the short end of a long lever.

lazlo
01-12-2010, 02:07 PM
My cheap coax isn't "jumpy". I guess it is the luck of the draw with import tools, but barring a bad one, I couldn't see a reason to pay more for the name brand.

I have both (authentic Blake and a Chicom copy) and there are two big differences: the top of the Blake that the pusher rides on is lapped smooth and flat, and the dial indicator itself on the Blake is vastly better than the Chinese version. Better = smoother and more sensitive.

lazlo
01-12-2010, 02:12 PM
RE all the kvetching about Coax's threatening to break out in this thread and that did break out in the others, I was amused to discover that other thread had become famous in some local machine shops. They thought it was pretty funny peeps had such a hard time understanding both the value and the limitations of the tool. It was definitely a "roll their eyes" there-go-those-home-shop-guys-again kind of remark.
Beyond rolling their eyes did they offer any useful information to help define the limitations?

There was only one person questioning the usefulness and limitations of the Blake and it's clones in the other thread :)

As was said endlessly in that thread: the Blake is great for locating round features (holes, pins, etc). The 3D Taster it was being compared with is great for locating square workpieces, since you can touch off the two sides and the top, and zero the DRO in one setting.

The 3D Taster is meant for CNC setups, and not nearly as useful if you don't have CNC or a DRO, and it's not nearly as quick for locating round features.

Both the Blake and the 3D Taster are convenience items though -- you can do all the same setups with a DTI on a Zero-Set or similar quill clamp.

mochinist
01-12-2010, 02:37 PM
Beyond rolling their eyes did they offer any useful information to help define the limitations? Eye rolling, while fun to watch, has always been one of those useless reactions that causes me to roll my eyes in wonderment.:rolleyes:





:D

Mike Nash
01-12-2010, 02:45 PM
They thought it was pretty funny peeps had such a hard time understanding both the value and the limitations of the tool.
http://www.babble.com/CS/blogs/strollerderby/Peeps.jpg

Seems reasonable to me that something with marshmallow for brains might have somewhat of a problem understanding most anything.

BobWarfield
01-12-2010, 04:01 PM
Beyond rolling their eyes did they offer any useful information to help define the limitations? Eye rolling, while fun to watch, has always been one of those useless reactions that causes me to roll my eyes in wonderment.

It's funny how much of the content on this site consists essentially of eye rolling, isn't it?

Actually, they were much less critical of the indicators than the thread had been. In their view, they're the first thing to reach for if you want it to a thou. If it has to be better, they go for the DTI.

The eye rolling was at the over analysis and combativeness associated with what they viewed as an obvious and convenient timesaver. "Just another tool, why get so crazy about it?"

Cheers,

BW

oldtiffie
01-13-2010, 03:09 AM
I was going to let some of the comments "pass" but there are two that I'd like to take issue with.

The Blake and their clones are made for locating center of a feature such as a bore, outside diameter or center punch mark. They are not made for any other purpose such as tramming in a table.

They will kinda-sorta work, but that is not their intended purpose. Long drawn out descriptions of the missapplication of a tool or instrument serve no purpose but to confuse the beginner and obfuscate the issue.

The table from the Blake site is not an accuracy table, is is a table of correction factors for the different length stylii. The dial graduation values are not an indication of error, but are multipliers to indicate the relative value of the graduations with the various length stylii. When the indicator is centered to zero movement, it is zero movement. If there is a +- deviation from the zero point, it is +- the graduation times the multiplier. That is not error.

Jim.

The Blake web does not say that the co-ax should not be used for (any) other than the intended purpose nor does it say that doing so incurs a risk:
http://www.blakemanufacturing.com/pages/aboutus.html

dp's (Dennis's) video with the (curved/bent) feeler on the base of "tramming disk" would put far less force or pressure on the co-ax from pointer end to the spindle in the collet than the force resulting from indicating a tube/cylinder at the same diameter and settings. But the ("fake"/"import") co-ax clearly handles it OK - and I could reasonably extrapolate that to say that the Blake would handle it as well.

In fact, I am surprised that "Blake" does not add that as an additional benefit and use.

Now the next one (by Lazlo)


Originally Posted by BobWarfield
My cheap coax isn't "jumpy". I guess it is the luck of the draw with import tools, but barring a bad one, I couldn't see a reason to pay more for the name brand.

I have both (authentic Blake and a Chicom copy) and there are two big differences: the top of the Blake that the pusher rides on is lapped smooth and flat, and the dial indicator itself on the Blake is vastly better than the Chinese version. Better = smoother and more sensitive.

I agree with Bob as his experience is the same as mine - a good tool.

Perhaps Lazlo got a really good "Blake" and a really bad "clone" (can happen) but perhaps he has bad case of myopia and xenophobia.
http://en.wikipedia.org/wiki/Xenophobia

Sinophobia too?
http://en.wikipedia.org/wiki/Anti-China

And this one (Lazlo again):


Originally Posted by dp

Originally Posted by BobW
RE all the kvetching about Coax's threatening to break out in this thread and that did break out in the others, I was amused to discover that other thread had become famous in some local machine shops. They thought it was pretty funny peeps had such a hard time understanding both the value and the limitations of the tool. It was definitely a "roll their eyes" there-go-those-home-shop-guys-again kind of remark.

Beyond rolling their eyes did they offer any useful information to help define the limitations?


There was only one person questioning the usefulness and limitations of the Blake and it's clones in the other thread :)

As was said endlessly in that thread: the Blake is great for locating round features (holes, pins, etc). The 3D Taster it was being compared with is great for locating square workpieces, since you can touch off the two sides and the top, and zero the DRO in one setting.

The 3D Taster is meant for CNC setups, and not nearly as useful if you don't have CNC or a DRO, and it's not nearly as quick for locating round features.

Both the Blake and the 3D Taster are convenience items though -- you can do all the same setups with a DTI on a Zero-Set or similar quill clamp.

This is pretty well verbatim from the "other (co-ax) thread". I let it pass - just - but not now it has been repeated - here.


There was only one person questioning the usefulness and limitations of the Blake and it's clones in the other thread

I guess that's me as I certainly had a lot to say though I am not sure that is an accurate description of what I said.


As was said endlessly in that thread: the Blake is great for locating round features (holes, pins, etc).

Add "tramming".


The 3D Taster it was being compared with is great for locating square workpieces, since you can touch off the two sides and the top, and zero the DRO in one setting.

Nope.

Its pretty quick at locating centres - and just about anything else too. A good read and understanding of the manual and a good deal more creative and lateral thinking - and a lot less "blinkered" thinking will soon show that to be the case.



The 3D Taster it was being compared with is great for locating square workpieces, since you can touch off the two sides and the top, and zero the DRO in one setting.

That's true - mainly. There is not need for DRO's - but they will certainly help. Using lead-screws from the same direction when centreing/zeroing the "Taster" will do as well. All that is needed is a common desk-top calculator and a pen and paper.


The 3D Taster is meant for CNC setups, and not nearly as useful if you don't have CNC or a DRO, and it's not nearly as quick for locating round features.

Not true.

I haven't seen that on any of the original Taster or clone web sites.

The "Taster" zeroing feature is ideal for "blue-printing" in all 3 axis as well as setting the milling head tool in "X" and "Y". It is of no use in setting "Z" tool height in any mill - CNC included. In "Z" it is the tool itself that has to be accurately located. The Taster "Z" only measures relative and absolute distances - it does not set tool heights. Even the mill table or any designated horizontal surface on the job or mill etc. that can be used as a reference will do the job too.

These - and similar - set "Z" heights:
https://www.machineryhouse.com.au/Z-Axis-Preset-Gauges


Both the Blake and the 3D Taster are convenience items though -- you can do all the same setups with a DTI on a Zero-Set or similar quill clamp.

They are an improved convenience device - both of them.

I can do pretty well with a dowel accurately set up in a collet. All I need is good "feel" and eyesight (and no "tear-ar$ing" - just patience) and I can locate the required face and then apply the "off-set". Its been done that way since "day one" - and still is!!

Both the generic "Blake" and "3D-Taster" and their clones are a lot more useful than the manuals seem to imply or limit them to.

For general work, this laser indicator is hard to beat:
http://littlemachineshop.com/products/product_view.php?ProductID=2606&category=
Search for item 2606 if necessary.

I have one. Its very accurate and good value. I use it and the "pointer" on my "Wiggler"
http://i200.photobucket.com/albums/aa294/oldtiffie/measuring/Wiggler1.jpg

for a lot of my stuff or in conjunction with the 3D-Taster and ...................

Tra-la-la-la

...........................

(drum roll and bugles - then hushed silence)

............................

My "Fake Blake" co-axial indicator.

http://i200.photobucket.com/albums/aa294/oldtiffie/measuring/Co-axialindicator5.jpg

And last but not least.

There is no "Blake's Drum" for you to keep beating - but wait - there's more - see later.

Perhaps you could borrow "Drake's Drum":
http://www.traditionalmusic.co.uk/folk-song-lyrics/Drakes_Drum.htm

http://en.wikipedia.org/wiki/Drake%E2%80%99s_Drum

http://independentartistscompany.com/songs.aspx?SongID=25667&ArtistID=38255

You can be Blake's Drummer Boy
http://www.google.com.au/search?hl=en&source=hp&q=drake%27s+drummer+boy&meta=&aq=0&oq=drake%27s+drummer+

Ian B
01-13-2010, 05:24 AM
GWilson,

I don't think it makes any difference how long the arm is on a Blakes-type indicator when using it to tram a mill. If you double the arm's length, the tip will see twice the vertical movement, but the mechanical ratio of the longer lever will (near enough) half the dial gauge reading.

fwiw, I'll stick with using a plunger-type dti on an arm - I was lucky enough to find a nice Mitutoyo one with a face & needle on both sides, so no problems with reading it at any point on its arc - something like this one:

http://www.mitutoyo.co.uk/MitProd/mtopr.nsf/UNIDS/87ED026B3D1E2AF78025695300348694!Opendocument

Ian

JCHannum
01-13-2010, 08:26 AM
Jim.

The Blake web does not say that the co-ax should not be used for (any) other than the intended purpose nor does it say that doing so incurs a risk:
http://www.blakemanufacturing.com/pages/aboutus.html

That is pretty fuzzy logic Tiff. I just took a close look at my pickup owner's manual and nowhere does it say not to drive it over a cliff, I guess this means that is OK to do. You will have to come up with something better than that.

lazlo
01-13-2010, 10:08 AM
I agree with Bob as his experience is the same as mine - a good tool.

Perhaps Lazlo got a really good "Blake" and a really bad "clone" (can happen) but perhaps he has bad case of myopia and xenophobia.

It's pretty simple Tiff -- can you tell the difference between a $10 Chinese dial indicator (which is what you're getting in a $40 Blake clone) and a $100 Swiss, Japanese or American indicator (which is what you're getting with the real Blake)? Or the $200 German indicator you're getting on the Haimer 3D Taster?

Why do you think the German (Haimer) and Swiss versions of the Blake are $500 and $3,000, respectively? Is your $40 Chicom Blake just as good as the Deckel Centricator? :D

If your Chinese Blake clone is good enough for your purposes, that's great. Like several other folks here have posted, the Chinese Blake clone that I bought is not good enough for mine, so I bought a used Blake, and it's much more accurate, repeatable, and reliable.

MickeyD
01-13-2010, 10:31 AM
I had a Chinese copy and with patience I could hit plus or minus .001" pretty easily. The Blake does plus or minus .0005" in a lot less time without having to sweat. I checked these numbers with my 3D tester which repeats at .0001" on my cnc mill if I leave the halogen light off inside. For most of what I do the Chinese copy would be fine, but the Blake is much more confidence inspiring and just a pleasure to use. Once you go Blake you never go back.

oldtiffie
01-13-2010, 06:41 PM
Originally Posted by oldtiffie
Jim.

The Blake web does not say that the co-ax should not be used for (any) other than the intended purpose nor does it say that doing so incurs a risk:
http://www.blakemanufacturing.com/pages/aboutus.html

That is pretty fuzzy logic Tiff. I just took a close look at my pickup owner's manual and nowhere does it say not to drive it over a cliff, I guess this means that is OK to do. You will have to come up with something better than that.

Jim.

"Fuzzy" or not - it makes sense.

"Common sense" has to be presumed - both with the co-ax and the P-U truck.

I really, really DO try to NOT to use a micrometer as a clamp on the welding bench - same as I try not to use my "G" clamps as a micrometer on the lathe and mill (even the grinders!!) - but looking at some of the work that I do I'm not sure that I didn't - not that it matters here.

Provided that the tool is able to do a job well enough and the tool is neither abused nor damaged, and due care is taken, I see nothing wrong with a bit of lateral thinking.

One of the best ways to stifle work and innovation in the shop - HSM or "other" - is to have everything "by the book" which extended means that if the "right" tool is not there the job cannot be done unless or until that "right" tool is acquired but "MUST" be used the "One and Only Way".

That, taken to extremes, that is the "Militaritic" ("stand-over"!!) or the "my way or the highway" or "get the message or get the bus" approach which "brain-washes" people and strangles innovation and discussion.

Unfortunately, it is or has been all too obvious and prevalent in "Trade" schools and similar "teaching" situations over a very long time.

I'd hate it to happen any more often than it does here either.

I think, that despite our often different ways of seeing things or solving problems, that we do agree more often than not.

I must say that I've had to re-think a few things because of our discussions.

I am quite comfortable with that.

I have a bit more to do on this thread as well.

oldtiffie
01-13-2010, 06:55 PM
I had a Chinese copy and with patience I could hit plus or minus .001" pretty easily. The Blake does plus or minus .0005" in a lot less time without having to sweat. I checked these numbers with my 3D tester which repeats at .0001" on my cnc mill if I leave the halogen light off inside. For most of what I do the Chinese copy would be fine, but the Blake is much more confidence inspiring and just a pleasure to use. Once you go Blake you never go back.

Thanks Mickey.

That makes a lot of sense.

I don't doubt that many "Blakes" are very good and that some clones are pretty poor, but there are a lot of both in between - its matter of know which is better - and getting it.

Further, its a matter of how much accuracy - and consistency - you/I/any one else really needs, how much he needs to pay or how much he can afford to pay to decide which co-ax he needs and can afford - or not.

Perhaps I'm lucky in that perhaps the US supplier I bought mine from takes a lot of care with QC, but the clone I have is very good. I gave it good run through its paces as I was looking for the fault we had here in a shop I was in with a similar product from a very well-known "name" supplier. I couldn't find or replicate that - or pretty well any - problem with the "fake" co-ax that I have.

I will do some further work on this thread.

dp
01-13-2010, 07:53 PM
I will do some further work on this thread.

I'd like to see some posts that demystify the co-ax tool. There's a lot of misunderestimating what it can do, and some mystery about what it cannot do. That should be a stand-alone thread that starts out like a quickie how-to tutorial.

One issue in particular that is really not well understood is the issue of sensitivity of the gage under various configurations and uses.

Hot Bob
01-13-2010, 07:57 PM
Ok, thanks guys. I just picked up a Blake on ebay for $100 BIN. Can't wait to see how easy my life will become.

Bob

madman
01-13-2010, 09:50 PM
Co axial Indicators have more moving parts than a regular simple dial test rig. (indicator im saying) I think if you havent developed youre skills at simple indicating why get something like a coaxial that usually is not as accurate and also costs more? I think a mirror (bicycle one is great) for looking at youre indicator needle is the way to go. I recall many years ago ads on our bulletin board for quite a while Coaxial indicator for sale cheap but NO ONE In our Aerospace shop would touch it weven if it wasd given to them for free/ Nice looking Gadget Yes>> But yeah a Gadget keep it simple and things will be good i say /

oldtiffie
01-13-2010, 10:58 PM
The co-axial indicator (aka "co-ax") "Blake" and "others".

http://i200.photobucket.com/albums/aa294/oldtiffie/measuring/Co-axialindicator1.jpg

http://i200.photobucket.com/albums/aa294/oldtiffie/measuring/Co-axialindicator5.jpg

I think we need everyone to have the data that some of us who have it are discussing, otherwise its a "lock-out" for those that don't have it.

First of all, the "Blake" - what it is and what it does:
http://www.blakemanufacturing.com/pages/aboutus.html

Note that it does not say that the dial readings are "Total Indicated Run-out" (TIR) but it seemed safe to assume that it is (but only with the 2" feeler) - but see later:
http://www.blakemanufacturing.com/pages/coaxvalues.html

Its equally safe to assume that this applied to the "clones" (aka "fake Blake) co-ax units as well.

Here is the hand-book that came with my (new) "fake" - co-ax but note that the page numbers are as I noted them by hand (at the bottom).

Note too that this book says the indicated dial reading calibtation is "Off-set" is 0.0005" - so the TIR is actually 0.001" per indicator dial calibration (but only with the 2" feeler - not with the 3" or 4" feelers (see previous posts re the table from the Blake web site) - here it is again:
http://www.blakemanufacturing.com/pages/coaxvalues.html.

I presume that the "fake" is the same as the (real?) "Blake" (see later re TIR):
http://i200.photobucket.com/albums/aa294/oldtiffie/measuring/Co-axindicatormanual1.jpg

http://i200.photobucket.com/albums/aa294/oldtiffie/measuring/Co-axindicatormanual2.jpg

So what is TIR?

It is the amount that the indicated surface/hole is "off" from the co-ax centre. It will have a "HI" and a "LO". The actual amount that the Co-ax is "off-centre" is half the TIR.

So with a TIR of 0.0005" (5 tenths) the actual "off-centre" is half of that indicated amount ie 0.0005/2" = 0.00025" (2 1/2 tenths).

And that is with the needle swinging the full "half thou" (0.0005") on the indicator dial. The less the needle swings and the closer it gets to being still/stationary the more accurate the location is.

BUT!!

If the dial readings are OFF-SET and NOT TIR as we normally know it then the 0.0005" is the Off-set which would be a TIR of 0.001" as we normally understand or expect it when using an indicator on a hole or cylinder in the lathe or mill.

So - remember - the co-ax is showing "off-set " and NOT "TIR".

I will deal with the "3D-Taster" and the "Wiggler" in their similar roles and functions later.

lazlo
01-13-2010, 11:33 PM
Ok, thanks guys. I just picked up a Blake on ebay for $100 BIN. Can't wait to see how easy my life will become.

LOL! It will center itself. Trust me :p

Roy Andrews
01-15-2010, 11:02 PM
i had a blake which i purchased for full price after using a few and liking them. it was "borrowed" from my box and has never returned. my uncle got a copy and really liked it so i thought what the hell and got one. then another then another..they were touchy and inconsistent. i finally quit returning them and gave it to my cousin. a year later i had a chance to get a Haimer 3D at an auction and got it. i like this as much as the blake maybe more but i had gotten used to using an indicator and use the 3D very little. also there is always the fear of breaking that pricey unit.

everyone i know who has one and has let others use it has gotten it back broken at least one time. my blake was repaired twice. always returned in perfect working order. i have learned though, the 3D i wont even let my wife touch.

oldtiffie
01-16-2010, 10:04 PM
Originally Posted by oldtiffie

I will do some further work on this thread.


I'd like to see some posts that demystify the co-ax tool. There's a lot of misunderestimating what it can do, and some mystery about what it cannot do. That should be a stand-alone thread that starts out like a quickie how-to tutorial.

One issue in particular that is really not well understood is the issue of sensitivity of the gage under various configurations and uses.


Thanks Dennis.

I will leave this thread to be "just co-ax" as its in dire peril of discussing a lot that isn't "co-ax" related and getting hi-jacked in the process..

I have a few (??? me ??? few????) items to cover regarding circles and cylinders - so will start a separate thread.

The "co-ax" will (have to) get a mention - even if just only "in passing".

It should "fit in" with this co-ax thread pretty well as it will be a sort of "follow on" and related thread.

>>>>>>>>>>>>>>>>>>>>>>>>>>>>